A jaw chuck can have a mounting body which can be connected to the drive or headstock spindle of a lathe for rotation about a machining axis, and an associated pivot assembly or unit.
For clamping or similar retention of a respective workpiece, chuck jaws are provided. The clamped workpiece can be moved, together with the chuck jaws, about a pivot axis, to thereby alter the machining axis of the workpiece in conformity with the directions of the axes of operation, or processing planes, of the workpiece.
This pivot axis, in turn, extends perpendicularly (a) with respect to the axis of rotation of the main or operational spindle and (b) with respect to the axes of operation of the respective workpiece.
It has been shown, for example in German Patent Nos. 1,214,974 and 2,128,618 or in German Patent Publication (DE-OS) No. 1,930,870 in hitherto known swinging-type chucks of this type that the axis of rotation of the mounting body and the axes of operation of the respective workpiece are disposed in a common plane, i.e. are not skew to one another. The pivot device is then adapted to serve in such a way so as to align the respective tool with its axes of operation in sequence and parallel with respect to the axis of rotation, without necessitating re-mounting or re-clamping of the workpiece.
Such options, however, are not available for workpieces in which the axes of operation are spaced from one another at a given distance of separation. Accordingly, in the case of a retained or clamped workpiece having one of its axes of operation aligned in the axis of rotation, the other axis is positioned outside and away from the axis of rotation and perpendicularly to the pivot or swing axis and, as a consequence, it is not possible to bring, by way of a corresponding rotation or turning of the workpiece, this axis of operation into the axis of rotation of the mounting body.
This problem is particularly pronounced for armature or valve housings which could not be machined heretofore with two axes in spaced relation without rechucking.